Fig. 1

Morphology and representative Immunohistochemical staining of the tumor. The tumor had an ulcer on the surface (a, ×20). It was composed of spindle-shaped cells and had atypia lymphoid cells within intratumoural blood vessels (b, ×200). There were the same cells in surrounding submucosa blood vessels (c, ×40 and d, ×400). The spindle cells were CD117 positive (e, ×200). The lymphoid cells were CD20 positive (f, ×200). The Ki67 proliferation index of the lymphoid cells was close to 100 % (g, ×100). The lymphoid cells were CD3 positive (h, ×200)